<style>

    #ball {
        width: 70px;
        height: 70px;
        margin: 50px auto;
        position: fixed;
        left: 20%;
        border-radius: 50%;
        background: linear-gradient(
            35deg,
            #ccffff,
            #ffcccc
        );
        animation-name: fade;
        animation-duration: 3s;
    }

    @keyframes fade {
        50% {
            left: 60%;
            opacity: 0.1;
        }
    }

</style>

<div id="ball"></div>